Originally Posted by DannoXYZ
But if you want to average 15mph, then you gotta put in the intervals @20mph every once in a while and do some sprints @30mph as well. Yah, it'll be a lot of suffering (not pain in my book), but it'll be worth it. Eventually with this type of training, your average will creep up surely.
If that 2mph increase is all that important in your book that its worth "a lot of suffering" than go for it. Doesn't sound in my book like a good promotion plan for promoting bicycling.